Could someone recommend a good chair for a photo retoucher?

I have a chair by a company called Schiavello (the Liberty Mesh) but it's getting on and I never really liked how the back just kind of bends back and there's no way to fix it straight.

With photo retouching my arms are constantly over the front of the desk so it would be good to have a good back that sort of encourages me forward I guess. I know nothing about ergonomics so feel free to school me.

Thanks!